import sys, bisect, math, itertools, string, queue, copy
# import numpy as np
# import scipy
# from scipy.sparse.csgraph import floyd_warshall
from collections import Counter,defaultdict,deque
from itertools import permutations, combinations, combinations_with_replacement
from heapq import heappop, heappush, heapify
from fractions import gcd
# input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')
    
    
if __name__ == "__main__":
    main() import sys, bisect, math, itertools, string, queue, copy sys bisect math itertools string queue copy from collections import Counter,defaultdict,deque from itertools import permutations, combinations, combinations_with_replacement from heapq import heappop, heappush, heapify from fractions import gcd sys.setrecursionlimit(10**8) sys.setrecursionlimit sys setrecursionlimit 10**8 10 8 mod = 10**9+7 mod 10**9+7 10**9 10 9 7 def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')
    
     main n = int(input()) n int(input()) int input() input if n >= 30:
        print('Yes')
    else:
        print('No')
    
     n >= 30 n 30 print('Yes') print 'Yes' print('No') print 'No' if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main mod = 10**9+7 10**9+7 mod def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')
    
     def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')
    
     main
import sys, bisect, math, itertools, string, queue, copy
# import numpy as np
# import scipy
# from scipy.sparse.csgraph import floyd_warshall
from collections import Counter,defaultdict,deque
from itertools import permutations, combinations, combinations_with_replacement
from heapq import heappop, heappush, heapify
from fractions import gcd
# input = sys.stdin.readline
sys.setrecursionlimit(10**8)
mod = 10**9+7

def main():
    n = int(input())
    if n >= 30:
        print('Yes')
    else:
        print('No')
    
    
if __name__ == "__main__":
    main()